In order to align the blade of a prior art miter saw with a cutting line on a workpiece, the operator must typically lower the saw to determine if the blade is aligned with the cutting line. If necessary, the saw is raised and the workpiece is maneuvered to improve the alignment, and the saw-lowering procedure is repeated. When precision cutting is required, this procedure is extremely time-consuming, and the desired precision is often not achieved, resulting in wasted time and material.
Further, miter saw blades have a discreet width. The cutting line, which is generally a pencil mark on the workpiece, also has a discreet width, further complicating alignment. For example, if the blade is centered directly over the cutting line, the cut in the workpiece will be inaccurate by an amount approximately equal to half the width of the blade. Consequently, it is often difficult to determine precisely where the blade will engage the cutting line.
Belt-driven miter saws with fixed center pulley systems are known in the art. While belt-driven miter saws have the advantage of producing less noise and vibration than gear-driven systems, the fixed center pulley systems used on prior art miter saws do not have the capacity to compensate for stretching and wear of the drive belt. Once the drive belt becomes stretched, it must be replaced. Further, the drive belts used on fixed center pulley systems must be manufactured to a close tolerance because there is no capacity in the fixed center pulley systems to adjust for manufacturing variation in the belt. Close tolerance belts tend to be more expensive to manufacture.
Another problem with fixed center pulley drive systems for miter saws is that the blade pulley tends to interfere with the depth of cut possible with the miter saw. Ideally, a miter saw with a 10" diameter blade should be capable of cutting a nominal 2".times.6" (typically having an actual cross-sectional size of 1-1/2".times.5-1/2") workpiece when the blade is oriented at 90 degrees relative to the fence and a nominal 4".times.4" (typically having an actual cross-sectional size of 3-1/2.times.3-1/2") workpiece when the blade is oriented at 45 degrees relative to the fence. However, known blade pulleys tend to be larger than the blade flange used to anchor the blade to the miter saw, thereby reducing the depth of cut possible with the blade. Previous attempts to use small diameter pulleys which that do not interfere with the cutting radius of the blade have resulted in extensive heat buildup on the pulley system, causing accelerated wear of the drive belt and damage to the pulleys.